1. Field of the Invention
The present invention relates to a magnetic operating mechanism for switches, particularly, relates to a manual tripping device for the magnetic operating mechanism.
2. Description of Related Art
In the switches, such as vacuum switches and the like, used in a power transportation or distribution system, a magnetic operating mechanism in which permanent magnets are implemented has generally been used for the switching operation. The magnetic operating mechanism makes an opening/closing operation of contacts in the switches using electromagnetic force based on magnetic fields, which are generated by discharging electric energies charged in capacitors previously from a power source. After the switching operation, the opened or closed position in the switches is entirely held by electromagnetic force based on magnetic fields of the permanent magnets.
The above described switches having such the magnetic operating mechanism are needed to open the contacts manually when the power supply is interrupted by the reason of power suspension, for instance.
Japanese Patent Publication (non-examined) 55531/1996 describes an example of such a conventional manual operating device in which a tripping mechanism is used to engage or disengage a latch pin and a latch lever. In the normal condition, an opening operation is made by exciting the coil of a tripping magnet, but in the abnormal condition such as power failures, the opening operation is done manually through a pulling-in lever by rotating a handle attached on manually-operable shaft.
However, the conventional mechanism mentioned above requires for extremely complicate structure consisting of many parts. In addition, switch gears in which the switches are installed are used in a parallel arrangement of a plurality of units in many cases, so that each switch must be provided with such tripping mechanism. Therefore, manufacturing process is complicated due to the increase in the number of parts, and the operating device is upsized by parallel arrangement of the plurality of units, resulting in increase in a manufacturing cost.